1. Field of the Invention
The present invention relates to a receiver for high frequency electromagnetic oscillations having a frequency readjustment which contains a voltage-driven oscillator.
2. Description of the Prior Art
Undesired frequency fluctuations in systems are usually suppressed by means of frequency reverse feedback circuits. For this purpose, a frequency discriminator can be provided in the reverse feedback branch, which frequency discriminator feeds an oscillator, for example the local oscillator of a converter, with its amplified output voltage the oscillator being voltage-controlled and involved in determining the signal frequency.
The frequency readjustment of unmodulated or narrow band signals is relatively noncritical. Particular problems, however, occur given broad band signals such as, for example, pulse shift keying (PSK) signals, in which the entire spectrum must be evaluated in the discriminator because of the missing carrier. With such a system, control errors can occur not only due to unstable frequency discriminators but, rather, also due to non-constant amplitude slopes.